Among conventional control devices, a PLC (Programmable Logic Controller) is a programmable control device. The PLC acquires high-speed/large-capacity data from an external sensor, computes the data according to a sequence control program described in a ladder language or the like, and outputs a signal for controlling an external apparatus.
In recent years, in a monitoring control system that links a control device such as a PLC with host information system software such as an MES (Manufacturing Execution System) or an ERP (Enterprise Resource Planning) or treats high-speed/large-capacity process data by dedicated software called SCADA (Supervisory Control And Data Acquisition), for example, the control device is connected to an apparatus such as a sensor or an actuator in a plant, the apparatus is controlled by the control device, the SCADA reads measurement data of the apparatus stored in a memory of the control device, monitors the plant on a real-time basis, store data in time series, and graphically displays collected data on an HMI (Human Machine Interface).
A conventional control device is explained. The conventional control device uses a model for executing specific processing when a certain event occurs, defines a condition corresponding to the event occurrence as a start condition, and defines processing executed by the event occurrence as an action. The start condition and the action related to the start condition are managed in units of a job. The conventional control device defines, in job information, start conditions, all actions executed according to the start condition, and start patterns of the actions and, when a certain start condition holds, executes the actions according to a start pattern defined in the job information corresponding to the start condition (see, for example, Patent Literature 1).